Buffers and polishing

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Bill DeShivs

Bill DeShivs

Knifemaker / Craftsman / Service Provider
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Polishing lathes, or "buffers" are extremely versatile tools.
While they are generally thought of as something you use to make things shiny, they can do much more than that.
Most buffers run at either 3650 RPM or 1750 RPM. The lower speed is generally more useful, but don't discount the faster machines. They can be effectively "slowed down" by using smaller diameter polishing wheels.

The cheapest bench buffer you can rig up is a simple bench grinder with the wheel guards removed, and polishing wheels mounted. While not the ideal buffer, these can be quite handy. I use several in my shop-each dedicated to a specific purpose.

Dedicated buffing machines usually have extended shafts to give more room to move the work against the spinning wheels.

Buffing machines can also be built using arbors and pillow blocks, belt-driven by an electric motor.

There are machines generally referred to as "dental polishing lathes" that are extremely precise, versatile polishing tools. These generally use tapered spindles for quick threading on/off of polishing wheels. These machines are often dual-speed machines and can be found on Ebay at inexpensive prices. You don't even want to know what they sell for new-trust me, they are expensive!

Note: I'm no polishing expert, and I'm doing this off the top of my head. Stacy and other experienced polishers-feel free to edit, correct, add to, or question any of this!

Check each post for edits and additions as they come to me!
 
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Since we have covered the basic machines, now lets talk about the polishing wheels, and what they do.
Cloth wheels are available in cotton muslim, denim, treated cotton- maybe others.

The cloth wheels can be either:
hard sewn: usually used with aggressive compounds for cutting
Sewn muslin: a looser weave between hard sewn and loose. A good general-purpose buff
Loose cotton: for fine finishes. Loose wheels are more prone to grabbing work than others.

Sisal wheels are used with aggressive compounds to remove scratches from grinding.

There are felt wheels in different hardnesses. These are good for keeping surfaces flat, and for high polishing with the proper grits.

Wood laps are simply wooden wheels that are charged with polishing compounds. Like felt wheels, they keep surfaces flat and can provide a high polish with finer compounds.

Rubber wheels are hard rubber containing abrasive compounds in different grits. The more aggressive grits can actually remove quite a bit of metal.

Scotchbrite and similar wheels are made of a plastic mesh that is embedded with abrasives of varying grits. These wheels are good for smoothing and for satin finishes.

Wire wheels: generally used for removing rust, dirt, or scale
 
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Another wheel that is useful in the knifemaker's shop is the expanding drum sander. These are flexible rubber wheels that use abrasive belts. Centrifugal force expands the drum to hold the belt in place. They can be used much like a contact wheel on a belt grinder. Belt life is much shorter than grinder belts.
A similar wheel is called a "Cone-lock" wheel, or some variation of the spelling.

There are texturing wire wheels that are available that will give a sand-blasted effect.
 
Polishing compounds:

This one will probably be lengthy and might be edited several times.

There are so many compounds we won't be able to cover all of them here. We all have our favorites, and we haven't all used each other's favorites-so all I can go on is my own experience here.

There are the "standard" compounds: emery, tripoli, and the various rouges. Emery is generally a black bar that is fairly aggressive. Often used on sisal wheels. Tripoli is a semi-agressive compound that is used at low speed on loose buffs to polish plastics and soft metals. The rouges are formulated for various metals for high polish.

Specialized grinding compounds are available in grits from 180-1500.
These are available in grease-based bars, "greaseless" (plastic-based) compounds, or brush-on compounds that are glue-based. Brush-ons are applied and allowed to dry before using.
Grinding compounds are very useful for pre-polish of steel. The greasless compounds are some of my favorites used on spiral sewn muslin buffs.

NOTE: you must use a separate polishing wheel for each compound! Be careful of cross-contamination between buffs.

Getting confused yet? We are just beginning.
I'm giving you all this info so that you can better make informed choices when buying your supplies.
 
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I'm sure most of you just want to know what buffer, wheels and compounds to get-and how to use them. We'll get to that soon.
Polishers are so useful I have about 10 in my shop. My business is not just making knives, so my requirements will be different from yours.

My most used buffer is on my Grizzly 2x72 grinder. I use an 8" concentric-sewn muslin wheel and green chrome polishing compound. With lots of hand-sanding beforehand, this 1750 RPM machine will effectively give a mirror polish on most metals and handle materials.

SAFETY ALERT!: polishing creates abrasive dust that you do not want to breathe! At least use some sort of mask when polishing. A respirator is better.
Note the cardboard dust hoods. Should your hand get pulled into them, they won't cut you.
 

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Hey Bill, do you think the Grizzly buffer is close enough in quality to the Baldor equivalents, assuming you've used them? Obviously the grizzly version is significantly cheaper at retail.
 
There is no finer buffer than a Baldor. you can never go wrong buying Baldor. I have used many different brands.
Grizzly makes an OK buffer. I have 2 in my shop and use them a lot. Baldors are very expensive. Grizzlys aren't.
 
I'm assuming the mods don't want anyone to comment in this thread, as they have given me the option to keep it locked.
 
Here is a picture of my Baldor dental lathe.
If you want only one polishing machine in your shop, this is probably the one to have. It uses tapered spindles, so you can easily switch buffs.
The machine is also dual speed. Shop Ebay for these.

 
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Here is a Grizzly 1 HP 3450 RPM buffer. This is a serious machine!

 
These little Delta variable speed 1/2 hp machines are pretty useful. The wheels are close to the body-a disadvantage.
I never use mine at any speed except the lowest.

 
I didn't lock your tread, but keeping it locked will probably cut down on erroneous info. The info you have given is good solid stuff.
 
Thanks! More coming soon, but have a family function today.
 
Here are a couple of "greaseless" compound bars. They use a plastic binder that melts under the heat of friction when applying to the wheel. They are aggressive compounds. I use the 320 and 600 grits on my 1 hp Grizzly buffer.

 
Hey Bill, how about giving a recommendation on grit progression for someone shooting for a mirror/polished finish on steel?


My tip: If you take a fitting or component of a knife to a polished finish, you can easily step back to any grit satin finish quickly and easily, and get a true finish to that grit. The buffing process will also show you where you may be missing courser grit scratches. Jim Crowell showed me this trick on buffing the bottom of a ricasso and the spine of a blade. I applied it to lots of other things, like bolsters, etc. The only tricky part is keeping everything flat.

Buffing, then stepping back to fine scotchbrite wheel looks killer, and is easy to touch up if it gets handling marks.
 
Using a dust collection system with buffers is a good idea.
Mine have blast gates that I can open/close depending on which machine I'm using.
Obviously, it doesn't suck up everything, but you would be amazed at the quantity that it does collect!

 
Pictures and maybe a video coming when the flood waters recede from my back yard and I can get to the shop without boots!
 
HOW to buff:
Buffers should run counterclockwise. Forget running them backwards or using them from the side. Some people learn this way, but it isn't the CORRECT way to polish.

Ideally, the buffer should be rigidly mounted at waist height or slightly higher- wherever feels comfortable to you.

Polish on the BOTTOM THIRD of the wheel.

Do not present any edge-sharp or otherwise, to the spinning wheel. Edges should always be down toward the bottom of the wheel.

Let the machine do the work. The harder you press, the more likely you are to have the buffer grab. The work must be firmly but delicately presented to the spinning wheel.

Once you have a little practice doing this it becomes pretty natural, but never become complacent and/or negligent with any power tool-that's when mistakes happen.
 
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